Undergrowth

About: Undergrowth is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 11911 citations. The topic is also known as: understorey & underbrush.

Nematodes associated with forest and woodland trees in Scotland

Abstract: SUMMARY A survey of the nematode genera associated with trees in Scotland showed that Tylenchus sensu lato, Aphelenchoides, Tylencholaimus, Trichodorus, Helicotylenchus, Rotylenchus, Criconemoides s.l., Hemicriconemoides, Tylencho-rhynchus, Pratylenchus and Paratylenchus s.l. were commonly found in soil samples collected from around the roots of coniferous and deciduous trees. Only Criconemoides s.l. appeared to have a significant preference for deciduous woods. The presence of undergrowth in woods and forests was associated with significantly greater numbers of plant-parasitic nematodes. Measurements of abiotic factors indicated that, in mineral soils, pH affected the incidence of most genera, but soil type, moisture content and altitude had little effect.

Production of Herbaceous Vegetation in Openings and under Canopies of Western Aspen

Abstract: Extensive forests of quaking aspen (Populus tremuloides Michx.), which occur widely at intermediate elevations in the Intermountain and Rocky Mountain West, constitute an important resource, both esthetically and economically. The aspen type is esteemed among sightseers, picnickers, and campers because of its beauty. Aspen forests protect the soil of an important snow-collecting belt on western mountain watersheds. Although aspen is not one of the important timber species, aspen wood products are in considerable and increasing demand. Finally, the type supports undergrowth capable of furnishing a great amount of cover and forage for wildlife and livestock. On aspen range in good condition one may wade waist deep through a rich mixture of many plants, including species of Heracleum, Mertensia, Delphinium, Osmorphiza, Agastache, Erigeron, Rudbeckia, Senecio, Thalictrum, Agropyron, Bromus, Elymus, and Carex. Most aspen range in the Intermountain region is depleted from prolonged overgrazing, however, and palatable species that were formerly abundant are likely to be scarce or absent. Curiously, much less vegetation is produced in openings, as a rule, than beneath the aspen canopy.3 Usually the vegetation of openings is the sparser and shorter, and it tends to include a smaller proportion of desirable forage species (Houston 1954). It may, indeed, include undesirable species such as the annual Madia glomerata Hook., that are absent under the aspens. We have personally observed such differences in production and species composition on aspen ranges in Utah, Nevada, southern Idaho, western Wyoming, and western Colorado. These observations have included a great variety of sites with respect to soil and exposure, and many variations in character of vegetation. Why should such a difference in ground-cover production exist? Is it a product of those factors. responsible initially for the existence of openings in an aspen forest? Is it caused by differences in microclimate under and away from the aspen canopy? Is it a result of heavier grazing in openings than under the aspen? Or is it the result of interactions between some or all of these factors? Whatever the cause, this widely observed difference seems anomalous, because it would appearthat demands upon the environment by the aspen trees themselves might be expected to infringe on the needs of plants of the shrub and herb layers. Logically, therefore, being free of such competi-tion, the openings should produce more vegetation, not less, than equal areas under aspens. Such a relation has been described by Moinat (1956) in the Quercus gambelii type in southwestern Colorado, a zone somewhat warmer and drier than the aspen-fir zone. Moinat shows that production ofthe field layer in grassy parks is markedly higher than in scrub-oak thickets. Many trenching experiments (reviewed byKorstian and Coile 1938) have demonstrated the adverse effects of root competition by forest overstory on growth of native ground vegetation or artificially planted trees. Shirley (1945), in a study carefully designed to test the relativeeffects of shade and root competition of aspen anct jack pine on tree seedlings and planting stock in Minnesota, demonstrated a root-competitive depression of conifer growth, although not of sur-vival. Shirley's comment is that, "In these studies, however intense the root competition of the overwood, its effect on survival was more than offset by the benefits of the shade, provided this did not reduce the light intensity below 20 percent." Weknow of no experiments of this kind involvingwestern aspen except for Pearson's (1914) comparisons of survival of planted Douglas-fir under aspen and in openings. These showed better sur-vival under aspen.

Edge Effects Created by Clear-cutting on Habitat Use by Sika Deer on Mt.Goyo,Northern Honshu,Japan

Abstract: Clear-cutting increased the species diversity and amount of undergrowth plants in a habitat of Sika deer (Cervus nippon) on Mt. Goyo, northern Japan. The number of species increased from 15 to 48 as a result of clear-cutting. Among the plants,Sasa nipponica (a dwarf bamboo), an important forage plant for Sika deer, was predominant. Fecal pellets of deer were abundant in the forest and at the “adjacent zone” (from the edge to 150 m out of the forest) and thereafter decreased suddenly. The intensity of utilization ofSasa nipponica was also heavy in the forest, moderate at the adjacent zone and light 200 m from the forest edge. Since the amount of the bamboo in the forest was small, the removal of bamboo was greatest at the adjacent zone. Clear-cutting creates a favorable feeding area for Sika deer in this zone by increasing the available plant production and securing forest cover.